This invention relates generally to line or cable cutters, and, more particularly, to an automatic electrical line release system.
There are many instances wherein it is necessary to sever lines or cables at predetermined times. For example, line release systems find applicability in the release of drogue parachutes, the timed release of the canopy of a parachute, the actuation of parachute safety lines and in particular in the testing of a personnel parachute.
One of the basic requirements of personnel parachute testing apparatus is to simulate, as close as possible, the conditions the system will be exposed to in operational use. Many of these conditions are manually initiated by the parachutist during descent. One of these manually initiated conditions is commonly referred to as the four-line release. Four adjacent canopy suspension lines are released simultaneously. The four-line release serves two vital functions: (a) it greatly reduces canopy oscillation, and (b) it imparts a degree of directional control to the canopy enabling the parachutist to guide himself and avoid hazards at ground impact.
During testing, it is of vital importance to monitor the parachute performance prior to, during, and following a four-line release. For obvious reasons of personnel safety, the majority of personnel parachute testing is conducted using either torso or articulated dummies to simulate a live parachutist. The use or dummies, however, requires a means of simulating a four-line release.
Two methods have been used in the past: (1) Complete removal of the selected suspension lines prior to packing the parachute, and (2) Cutting the suspension lines during descent with time-delayed reefing line cutters. Both of these methods have serious limitations. In the first method, when a portion of the suspension system is not connected during the critical phases of canopy deployment and inflation, serious delays can be encountered which could cause severe canopy damage, damage or loss of the dummy, and seriously degrade the value of the test data. In the second method, a high cost is incurred in using reefing line cutters which are a one-time use item. The bulk which the cutters add to the suspension system induces an element into the test system which would not be present in an operational configuration. This additional bulk could adversely affect the overall performance of the system under test.
It is therefore essential to provide a line cutting system which is not only highly reliable in operation, but which also enables specific performance parameters to be measured, is reusable, and has a minimal initial and inservice cost.